TR-462 Basin Approach to Address Bacterial Impairments in Basins 15, 16, and 17

Authors: L. Gregory, M. Brown, K. Hein, K. Skow, A. Engling, K. Wagner, T.A. Berthold

In the 2012 Texas Integrated Report and 303(d) List, approximately 48% of the 568 impaired water bodies were caused by high bacteria levels. Once a water body has been listed, the Clean Water Act requires action to be undertaken to restore water quality in that water body. Several options exist to achieve this, which include additional monitoring, a standards assessment, development of a total maximum daily load (TMDL) or development of another watershed based plan such as a watershed protection plan. Traditionally, impairments have been addressed one at a time. In order to more efficiently address similar impairments within the same basin, more efficiently distribute resources, and with the hopes of preventing future listings within the same watershed, a new basin wide approach is being implemented in the Texas River Basins 15 (Colorado – Lavaca), 16 (Lavaca), and 17 (Lavaca Guadalupe). These watersheds, collectively referred to as the Matagorda Bay watershed have five water body assessment units impaired for elevated levels of fecal indicator bacteria: Carancahua Bay, Arenosa Creek, Tres Palacios Creek and two segments of the Lavaca River.

This report discusses the current and historical state of the study area and focuses on describing the physical, hydrological, climatic, and demographic conditions as well as potential sources of pollution. Information presented will be used in future water quality analysis and will assist in determining how to address bacteria impairments in the watershed. Information is compiled on a watershed level, summarizing all three basins, as well as within each basin where appropriate.